Paladin Labs Inc's experimental drug to treat a rare parasitic disease is effective and safe enough to be approved, an advisory panel to the U.S. Food and Drug Administration said on Friday. The drug, Impavido, is designed to treat three forms of leishmaniasis, a disease caused by a group of parasites known as Leishmania, which are spread by the bite of a female sand fly. The FDA is not bound to follow its advisory panel's advice but typically does so.